1. Technical Field
The present invention relates to a vehicle safety apparatus including an inflator for inflating an inflatable vehicle occupant protection device. In particular, the present invention relates to a heater for maintaining the temperature of an inflator within a predetermined temperature range.
2. Description of the Prior Art
It is known to inflate a device such as an air bag to help protect a vehicle occupant in the event of a vehicle collision or a side impact to or rollover condition of a vehicle. Although an inflator is typically designed to operate over a wide range of ambient temperatures, the inflator performs in a preferred manner within a narrow temperature range.
For example, if an inflator is at a temperature above the preferred temperature range, the gas output pressure or flow rate of the inflator may be substantially higher than desired for preferred inflation of the air bag. In contrast, if the inflator is at a temperature below the preferred temperature range, the gas output pressure or flow rate of the inflator may be substantially lower than desired for preferred inflation of the air bag.
It is known to use an electric heater, or other type of heater, to maintain the temperature of the inflator in a predetermined range.